On Mon, 30 May 2022 11:36:39 +0200, Charles Keepax wrote: > > On Mon, May 30, 2022 at 11:18:43AM +0200, Takashi Iwai wrote: > > On Mon, 30 May 2022 11:08:46 +0200, > > Charles Keepax wrote: > > > > > > On Fri, May 27, 2022 at 06:13:38PM +0200, Takashi Iwai wrote: > > > > On Wed, 25 May 2022 15:16:21 +0200, > > > > Vitaly Rodionov wrote: > > > > The idea to add / delete controls by the control element change > > > > doesn't sound good; as already mentioned in my reply to the previous > > > > patch set, the change of the control elements can be triggered too > > > > easily by any normal users who have the access to the sound devices. > > > > It means thousands of additions and removals per second could be > > > > attacked by any user. > > > > > > > > > > This I am a little less sure how we handle. I mean arn't there > > > already a few ways to do this? Both the existing ASoC wm_adsp > > > stuff, and the topology stuff (used on all new Intel platforms, > > > so very widely deployed) let you create controls by loading a > > > firmware file. Also within ALSA itself can't user-space create > > > user ALSA controls? Is there some rate limiting on that? How is > > > this issue tackled there? > > > > The creation of kctls via firmware loading would be OK, as the code > > path can't be triggered so frequently. Is it the case for this patch > > set? There was too little information about the implementation (and > > more importantly, how to use the controls), so it's hard to judge... > > > > Yeah that should be what is happening here. Although it looks > like this code might be removing all the controls if the firmware > is unloaded. I will discuss that with the guys, we normal just > disable the controls on the wm_adsp stuff. OK, that sounds good. Basically my concern came up from the code snippet doing asynchronous addition/removal via work. This showed some yellow signal, as such a pattern doesn't appear in the normal implementation. If this is (still) really necessary, it has to be clarified as an exception. thanks, Takashi
